This invention relates generally to devices and methods for placing a sensor at a selected site within the body of a patient. More specifically, this invention relates to an improved and relatively simple insertion set for quick and easy transcutaneous placement of a flexible thin film sensor of the type used, for example, to obtain periodic blood glucose readings.
In recent years, a variety of electrochemical sensors have been developed for a range of applications, including medical applications for detecting and/or quantifying specific agents in a patient's blood. As one example, glucose sensors have been developed for use in obtaining an indication of blood glucose levels in a diabetic patient. Such readings can be especially useful in monitoring and/or adjusting a treatment regimen which typically includes regular administration of insulin to the patient. In this regard, blood glucose readings are particularly useful in conjunction with semiautomated medication infusion pumps of the external type, as generally described in U.S. Pat. Nos. 4,562,751; 4,678,408; and 4,685,903; or automated implantable medication infusion pumps, as generally described in U.S. Pat. No. 4,573,994.
Relatively small and flexible electrochemical sensors have been developed for subcutaneous placement of sensor electrodes in direct contact with patient blood or other extracellular fluid, wherein such sensors can be used to obtain periodic readings over an extended period of time. In one form, flexible transcutaneous sensors are constructed in accordance with thin film mask techniques wherein an elongated sensor includes thin film conductive elements encased between flexible insulative layers of polyimide sheet or similar material. Such thin film sensors typically include exposed electrodes at a distal end for transcutaneous placement in direct contact with patient blood or the like, and exposed conductive contacts at an externally located proximal end for convenient electrical connection with a suitable monitor device. Such thin film sensors hold significant promise in patient monitoring applications, but unfortunately have been difficult to place transcutaneously with the sensor electrodes in direct contact with patient blood or other extracellular fluid. Improved thin film sensors and related insertion sets are described in commonly assigned copending U.S. Ser. Nos. 08/213,101, filed Mar. 14, 1994, now U.S. Pat. Nos. 5,390,671; 08/212,961, filed Mar. 14, 1994 now U.S. Pat. Nos. 5,391,950; and 08/239,960 now U.S. Pat. No. 5,482,473, filed May 9, 1994, which are incorporated by reference herein. See also U.S. Pat. No. 5,299,571.
The present invention relates specifically to an improved sensor insertion set adapted for quickly and easily placing a thin film sensor on a patient with sensor electrodes in direct contact with patient blood or other extracellular fluid.